As a next-generation wireless communication method, various technologies for 5G wireless networking have been introduced. Thereamong, research into a full-duplex communication method capable of simultaneously performing transmission and reception has been actively conducted. The full-duplex communication method can improve network throughput but cannot be implemented due to self-interference of a radio node.
Therefore, technology for performing a full-duplex communication method by cancelling self-interference has been introduced. For example, in [B. Chen, Y. Qiao, Q. Zhang, and K. Srinivasan, “AirExpress: Enabling seamless in-band wireless multi-hop transmission,” in ACM International Conference on Mobile Computing and Networking (MobiCom), 2015], a relay node transmits a training sequence such that the transmitted training sequence moves in an interference path to receive a sequence having overlapping interference signals. The overlapping training sequence is hierarchically analyzed to continuously estimate interference channels in reverse order, thereby cancelling the interference.
However, the method of hierarchically estimating and cancelling interference may cause error propagation if interference channel estimation is inaccurate. Of course, if the number of relay nodes increases, the full-duplex communication method can not be performed.